They use it to appeal to their main targeted audience (young white american males) who they believe love Metal music. It shows in everything they do and how they market. Even the ring girls they choose are geared to that demographic.
On that note I will say that I was pleasantly surprised to see that they used bonafide Brazilian women with their protoypical feminine body shape as ring girls for this event. Arianni is nothing more than a pretty face on the body of a teenage boy with breast implants to me. If she were at a club with those Brazilian chick i would completely ignore her in favor of them